Object access using variable instead of using Js.Dict

1

Hi All,
I’m using Object Module from rescript-core dependency. Not using Js.Dict.
let (personName, setPersonName) = React.useState(_ => {Object.empty()})

let nameKey = “name”
personName[nameKey]

At the moment, if I do that, the compiler assumes I’m attempting to access an array and prompts me for an array<'a>.

Getting error as,

This has type: {…“data”: Arr.t}
Somewhere wanted: array<'a>

Thanks in advance🙂

2

You will not be able to do it with that syntax. For dynamic access of object fields, you will need to use the get or set function of rescript-core. E.g.,

let o = Object.empty()

let key = "yo"
Object.set(o, key, 1)->ignore
Object.get(o, key)->Console.log->ignore

// o[key] <- ERROR!

Not the same question, but somewhat related:

3 Likes
3

I’m curious why you’re not using reScript records. They are much more type safe than trying to use the Object module in Core.

4

To add to that the ReScript type system with variants, options, records etc. can model almost anything in a totally type safe and convenient way.